When creating an event in your Google Calendar, you can set the time zone that you are creating the appointment for.
For example: If you need to schedule an appointment with a colleague in Singapore, you can set the time zone of the appointment to Singapore, then set the appointment time for the time you would like it to be in Singapore. When you add the appointment to your calendar, it will show at the time it will be in your own time zone.
To set the time zone for an appointment:
Create a new event and click on More Options
Enter a Title for the event
Click on the Time Zone link to the right of the start and end date and time
If you need to set the start and end times for the meeting in different time zones, click on the checkbox to use separate start/end time zones
Choose the required time zone(s) from the drop-down list
Click on OK
Choose the start and end date and time for the meeting in the time zone chosen
Save the appointment as normal
The appointment will show in your own time zone in your calendar.